Blasting in or Near Bodies of Water

Rock fragmentation using explosives is accomplished by confining an

explosive charge with-in the geology to be broken. When the charge is detonated

the geology immediately surrounding the charged drill hole is fractured by

initial shock energy. The by products of the rapid detonation combustion (gases)

expand the fractures and the geology is displaced in the direction of least resistance

(the nearest free face or surface). The displacing material and escaping gases

cause a measured impulsive increase to nearby atmospheric pressure (similar

but less intensive than a thunder clap).

When explosives are used under water to fragment rock the displacing materials

and escaping gases cause a measured impulsive increase in water pressure. These

pressures must be controlled to prevent harm to marine life.

When blasting occurs on land in close proximity to bodies of water (or even in

shallow waters) ground vibration is communicated through the ground surface to

the water. In stark contrast to deep under-water blasting, through his research,

Lewis L. Oriard was able to state “ In those cases, questions related to technology

and ground vibrations are not much difference from those where there is no water”.

Blasting in or Near Bodies of Water

Blasting in or Near Bodies of Water

SD plot illustrating limited

resulting water pressure generation

from nearby land blasting

(L.L. Oriard 1985).